<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script>
    var video = document.createElement('video');
    var div = document.createElement('div');

    div.appendChild(video);

    document.body.appendChild(div);

    console.log(document.body.contains(video), video.parentNode === document.body, video.parentNode === div)

</script>
</body>
</html>
